DESCRIPTION: The broad, long-term objectives of this proposal are to develop reagents and methods for the synthesis of carbon-nitrogen bonds.The principal investigator seeks to develop new divalent tin amide reagents and then use them to create new methods for making carbon- nitrogen bonds. It is stated that the new methodologies, based on these reagents, will be directed at the preparation of compounds of biological relevance, such as beta-lactams, and peptides. New tin(II) amide reagents are to be prepared via ligand metathesis reactions and characterized to determine their compositions and states of aggregation. These new reagents are to be used to convert esters to amides. The principal investigator also intends to examine the effect ancillary ligands have on the reactivity of tin, the types of amide that can be transferred from tin, and intramolecular amide forming reactions. He is to apply the new methodologies to the preparation of beta-lactams, and peptide linkages, optimizing the yield and determining whether racemization occurs. In particular, he is to examine the fragment condensation approach to peptide synthesis on solid supports. The final amide forming reaction he is to examine involves mixed carboxy amido tin(II) compounds. It is reported that these compounds are readily prepared from Sn(N(SiMe3)2)2, an amine, and a carboxylic acid, and give amides upon warming. The principal investigator is also to apply this methodology to the preparation of amides, lactams, and peptides.